World's End: My Keyword is One More Than Others - Chapter 1: Maintenance and betrayal

Working hard and living frugally, Wen Qian accidentally obtained Spatial abilities, followed by dreams about natural disasters. So instead of buying an apartment, she stocked up on supplies, changing from a city office worker into a countryside food blogger. Then, Wen Qian noticed that reports of disasters around the world were on the rise…

The male student, Fukai Nagamasa, ignores his studies for college entrance exams in favor of following the path to chuunibyou. As he fainted during night cramming session before the exams, he realized that he was transported to a parallel world as a feudal lord in the Sengoku Era. Not to mention that suddenly, he was marrying the sixth Demon King, Oda Nobunaga’s little sister, the one who was purported to be an unrivaled beauty?

“Missus, time to fulfil your duties!” Mu Yuchen demanded as he pulled Xi Xiaye closer with his arms intimately wrapped around her waist.

It was a meticulously planned feast for the powerful. Her fiancé had knelt down on one knee and proposed to her sister instead. Robbed of her right to her inheritance, she was prepared for the Xi family to throw her to the wolves.
As she slipped away from her family that had turned their backs on her, she found him — Mu Yuchen, the low-profile and reserved noble that ruled City Z and led Glory World Corporation.

“Mu Yuchen, let’s get married!” He looked up at her, then suddenly stood up.

“Where are you going?”

“Let’s go. Any later and the civil affairs bureau will be closed.”

- Description from Novelupdates

Originally born from a wealthy family, she ends up leading a vagrant life for fifteen years. However, when she is eventually found by her family, she falls into another devious plot and eventually dies tragically.